Review
Geosciences, Multidisciplinary
Amzad Hussain Laskar, Archna Bohra
Summary: A large part of South Asia relies on the Indian Summer Monsoon season for rainfall, which significantly impacts the socioeconomic conditions of developing countries in the region. The rise and fall of ancient civilizations in South Asia were influenced by the Indian Summer Monsoon, although this influence is not fully explored. Attempts have been made to correlate monsoon variation with the decline of civilizations, but more quantitative estimations of the impact of monsoon variability on cultural shifts are needed.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geography, Physical
Aashima Sodhi, Archana Das, S. P. Prizomwala, Chintan Vedpathak, Nisarg Makwana
Summary: The study provides a multi-proxy analysis of the Indian summer monsoon and climate change, finding that solar activity plays a significant role in modulating the monsoon strength and suggests a potential linkage with the North Atlantic region.
QUATERNARY INTERNATIONAL
(2022)
Review
Multidisciplinary Sciences
Som Dutt, Anil K. Gupta, Rahul Devrani, Ram R. Yadav, Raj K. Singh
Summary: The study reveals distinct spatial variability of summer monsoon precipitation in the Indian subcontinent during the transition period, with prolonged dryness in the western parts lasting 1000 years and shorter dry spells in the northeastern parts lasting 200-300 years. Strong El Nino conditions were associated with the millennial long dryness in the western parts but had limited influence in the eastern region. More high-resolution records from different geographic regions of India are needed to confirm if regional differences occurred during the transition period.
Article
Environmental Sciences
Jerry B. Samuel, Arindam Chakraborty, Anagha Paleri
Summary: Land surface utilization in the Indian subcontinent has significant impacts on the region's monsoon rainfall. An increase in forest cover generally leads to more precipitation in India, but the relationship is not linear due to spatial heterogeneity. The consequences of land surface alterations act through evaporation, net energy input, and moist stability, with different mechanisms dominating different regions. The findings have broader implications for other forcings and scenarios.
ENVIRONMENTAL RESEARCH LETTERS
(2023)
Article
Geography, Physical
Fang Wang, Binggui Cai, Chuan-Chou Shen, Hai Cheng, Miaofa Li, Tingting Li, Ming Tan, R. Lawrence Edwards
Summary: By analyzing a stalagmite record from northeastern China, this study reconstructed the East Asian Summer Monsoon (EASM) and regional precipitation between 5.82 and 4.77 kyr B.P. The findings suggest synchronous variations of the EASM across monsoonal China on decadal to centennial scales, and highlight the significant role of El Niño in modulating the EASM during the mid-Holocene.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Meteorology & Atmospheric Sciences
Kandula Subrahmanyam, M. V. Ramana, Prakash Chauhan
Summary: The study analyzes the rainfall patterns and intensities of the Indian Summer Monsoon, and finds significant changes in the contribution of each active spell to the total rainfall. The first and second active spells show decreasing and increasing rainfall contributions, respectively. The study suggests that the observed decline in monsoon propagation speed and the shift in cloud radiative forcing may partly explain these changes in the monsoon. The findings provide a better understanding of the role of active spells in the changing climate.
ATMOSPHERIC RESEARCH
(2023)
Article
Geography, Physical
Dandan Wang, Manyue Li, Shengrui Zhang, Qinghai Xu, Liwei Wu
Summary: The 4.2 ka event, the most abrupt climatic event during the transition between the middle and late Holocene, had a profound influence on the regional ecological environment and human cultural development. It led to aridification in the mid- and low-latitudes regions of the Northern Hemisphere. The event's structure was complex, with alternating periods of arid and wet conditions. In the Asian summer monsoon region, the response to the event was spatially and temporally synchronous in the northern and southwestern parts, but oppositely in the southeastern part. Sea-air interactions in the low-latitude region, specifically sea surface temperature anomalies and the variation of the El Niño-Southern Oscillation in the tropical Pacific, were suggested as the main driving mechanisms.
GLOBAL AND PLANETARY CHANGE
(2022)
Article
Geosciences, Multidisciplinary
Bethany Hobart, Lorraine E. E. Lisiecki, Devin Rand, Taehee Lee, Charles E. E. Lawrence
Summary: According to an analysis of benthic oxygen isotope records, orbital precession played a more significant role than obliquity in the Late Pleistocene swings in ice-sheet extent. The study compared the impacts of obliquity and precession on glacial cycles and concluded that the precession phase had a more significant effect on termination onset, especially for the largest events. This suggests that Late Pleistocene ice sheets were more sensitive to the precession forcing of Northern Hemisphere summer insolation intensity.
Article
Meteorology & Atmospheric Sciences
Shraddha Gupta, Zhen Su, Niklas Boers, Juergen Kurths, Norbert Marwan, Florian Pappenberger
Summary: A deeper understanding of the relationship between the Indian summer monsoon (ISM) and the East Asian summer monsoon (EASM) is important for improving subseasonal forecasting of extreme precipitation events. Using a complex network approach, two dominant synchronization pathways and associated atmospheric circulation patterns between ISM and EASM are identified. Additionally, certain phases of the Madden-Julian oscillation and the boreal summer intraseasonal oscillation are found to influence the synchronization of extreme rainfall events between ISM and EASM.
INTERNATIONAL JOURNAL OF CLIMATOLOGY
(2023)
Article
Geography, Physical
Mohammad Firoze Quamar, Ratan Kar, Biswajeet Thakur
Summary: The study reveals the gradual intensification of the monsoon and climatic amelioration in central India during the Late-Holocene, from sparsely wooded savannah to dense mixed tropical deciduous forest.
Article
Geosciences, Multidisciplinary
Sajani Surendran, K. V. Ajay Anand, Suraj Ravindran, Kavirajan Rajendran
Summary: Evaluation of century-long simulations of the CESM shows the model's ability to capture characteristics related to aerosols, clouds, convection, rainfall, and circulation over India during the summer monsoon season. The simulations reveal that aerosols have an indirect effect on warming the atmosphere and exacerbating the severity of breaks in the summer monsoon season, with dust aerosols playing a significant role.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Sarah M. McGrath, Steven C. Clemens, Yongsong Huang, Masanobu Yamamoto
Summary: The orbital-scale monsoon variability in India is not a direct response to northern hemisphere summer insolation, but rather reflects changes in moisture source and transport paths associated with changes in greenhouse gases and ice volume. The responses of Indian and East Asian monsoon systems at orbital scale are uncoupled and are driven by different forcings.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Meteorology & Atmospheric Sciences
M. Midhun, P. R. Lekshmy, Kaustubh Thirumalai, R. Ramesh
Summary: There is a common mode of interannual rainfall variability in the Sahel and Indian summer monsoon regions, with the influence of Pacific and Atlantic sea surface temperatures. This can be captured using stable isotopes observations.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Meteorology & Atmospheric Sciences
Shu Gui, Ruowen Yang, Feng Zeng, Jinxin Cheng
Summary: This study investigates the interdecadal variability of the interface between the Indian summer monsoon and the East Asian summer monsoon. Results suggest that this variability is closely linked to two air-sea coupled modes, which influence the strength of the East Asian summer monsoon by affecting the western North Pacific subtropical high and causing cyclonic and anticyclonic anomalies. In recent decades, the impact of one of these modes has weakened, while the other has become more influential on this variability.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Meteorology & Atmospheric Sciences
Shu Gui, Ruowen Yang, Feng Zeng, Jinxin Cheng
Summary: This study investigates the interdecadal variability of the interface between the Indian summer monsoon and the East Asian summer monsoon. Results suggest that this variability is characterized by a zonal movement associated with variations between the Indian summer monsoon and the East Asian summer monsoon. This variability is closely linked to two air-sea coupled modes, resembling the Asian-Pacific Oscillation and the North Atlantic tripole pattern. Modeling results confirm the influence of these patterns on the interdecadal variability.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Geography, Physical
Som Dutt, Anil K. Gupta, Hai Cheng, Steven C. Clemens, Raj K. Singh, Vinod C. Tewari
Summary: High-resolution proxy records from Mawmluh cave in northeastern India reveal sudden shifts in Indian summer monsoon intensity over the past two millennia, influenced by volcanic activity, solar insolation, and Inter-Tropical Convergence Zone dynamics.
QUATERNARY INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Satyabrata Das, Gyana Ranjan Tripathy, Santosh K. Rai, Mohd Danish, Divya Thakur, Som Dutt, Shushanta Sarangi
Summary: The study revealed that both sulfuric and carbonic acid play crucial roles in the chemical weathering processes in the Teesta River in the Himalayan river basins. The contributions of sulfate and carbonate-mediated weathering to the major cations are comparable in this basin.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geography, Physical
Anil K. Gupta, Raj K. Singh, Som Dutt, Hai Cheng, Steven C. Clemens, Gayatri Kathayat
Summary: Research on Indian monsoon variability in northeastern India reveals the influence of factors such as the southward shift of the Intertropical Convergence Zone, weak Atlantic Meridional Overturning Circulation, and land-sea heat contrast. The climate in northeastern India has experienced alternating wet and dry periods in the past 13,000 years, especially during the Younger Dryas cold event. Speleothem data suggests high-frequency shifts in the Indian summer monsoon following the termination of the Younger Dryas cold event.
QUATERNARY SCIENCE REVIEWS
(2021)
Article
Geology
V. K. Srivastava, B. P. Singh, Som Dutt, A. Aggarwal
Summary: The present study investigates the processes responsible for the occurrence of Middle Eocene dolomites in the Kachchh Basin in the western Indian Continental Shelf. The study identifies three types of dolomites and suggests an organogenic origin based on the presence of algal micritization and microbial covering. The study also reveals the different types of diagenesis experienced by the dolomites, as well as the potential sources of carbon and methane. The findings highlight the importance of understanding the processes and factors influencing dolomite formation in this region.
CARBONATES AND EVAPORITES
(2022)
Article
Geosciences, Multidisciplinary
Dipanwita Sengupta, Som Dutt, Subhojit Saha
Summary: Speleothems are important tools for reconstructing regional paleoclimatic conditions, but the validity of isotopic datasets is uncertain due to post-depositional recrystallization. This study investigates the relationship between speleothem physical and geochemical proxies to reconstruct regional climatic conditions in the northwestern Himalayas. The results show a coherence between isotopic and petrographic proxies for regional climate variability on a larger scale, but detailed petrography is needed to accurately interpret the paleoclimate conditions.
GEOLOGICAL JOURNAL
(2022)
Article
Environmental Sciences
Mamta Chauhan, Som Dutt, Anshul Sharma Manjul, Brajesh Singh, Vijay Kumar Garlapati
Summary: In this study, a high-altitude strain B. amyloliquefaciens was found to effectively convert potato peel waste into bioethanol, with a high ethanol yield. By optimizing the fermentation variables, Acinetobacter sp. was able to produce ethanol efficiently. This study not only evaluated the sustainability of microbial conversion of waste to energy and bioethanol production in the Himalayan region, but also introduced promising extremophilic microbial strains with starch-hydrolyzing and fermentation capabilities for bioethanol biorefinery.
Article
Environmental Sciences
Divya Thakur, S. K. Bartarya, H. C. Nainwal, Som Dutt
Summary: This study assesses the environmental and land use changes in the Soan Basin, western Himalaya, between 1999 and 2015, and examines their impact on groundwater quality and static water level. The results indicate that the increase in agricultural practices and insufficient water management have led to a deterioration in groundwater quality in the region.
ENVIRONMENTAL MONITORING AND ASSESSMENT
(2022)
Article
Multidisciplinary Sciences
Xiyu Dong, Gayatri Kathayat, Sune O. Rasmussen, Anders Svensson, Jeffrey P. Severinghaus, Hanying Li, Ashish Sinha, Yao Xu, Haiwei Zhang, Zhengguo Shi, Yanjun Cai, Carlos Perez-Mejias, Jonathan Baker, Jingyao Zhao, Christoph Spoetl, Andrea Columbu, Youfeng Ning, Nicolas M. Strikis, Shitao Chen, Xianfeng Wang, Anil K. Gupta, Som Dutt, Fan Zhang, Francisco W. Cruz, Zhisheng An, R. Lawrence Edwards, Hai Cheng
Summary: This study presents speleothem oxygen-isotope records with subcentennial age precision and multi-annual resolution to investigate millennial-scale events during the Last Glacial Maximum. The findings suggest adjustments to the age of Greenland and Antarctic ice cores, and highlight the importance of low-latitude hydroclimate dynamics in such events.
NATURE COMMUNICATIONS
(2022)
Article
Geosciences, Multidisciplinary
Dipanwita Sengupta, Som Dutt, Subhojit Saha, Rahul Devrani
Summary: This study examines the geotourism potential of the Bhiar Dhar cave near Chakrata, Uttarakhand, which showcases a variety of speleothem features in their natural form. The cave features are under threat and immediate actions are needed for its conservation. Developing a trekking route from Gorcha village can attract tourists and generate revenue in the region.
Article
Geography, Physical
Sumit Sagwal, Dipanwita Sengupta, Anil Kumar, Som Dutt, Pradeep Srivastava, Rajesh Agnihotri, Sanjay Kumar Singh Gahlaud, Partha Sarathi Jena, Ajay Shivam, Ravi Bhushan
Summary: Wildfires are crucial for regulating vegetation cover in terrestrial ecosystems. Paleofire records stored in sedimentary deposits provide temporal information on fire activity and climatic conditions. A study in the Ladakh Himalaya examined a peat sedimentary profile to investigate fire characteristics and reconstruct wildfires. The results shed light on the interaction between vegetation, fire, and human activity over the past 2.8 thousand years.
Article
Geosciences, Multidisciplinary
Rahul Devrani, Rohit Kumar, Som Dutt, Rongsenzulu Jamir
Summary: The study assesses a hermit cave system in the Lakhamandal valley, located in the Northwest Himalaya. The valley is known for its geological and historical significance, but the growing tourism and unorganized excavations pose urgent concerns. The study aims to validate the hermit cave complex as a geoheritage site through preliminary assessment and recommendations.
Article
Geochemistry & Geophysics
Pradeep Srivastava, Som Dutt, Shweta Singh, Sandeep Panda
Summary: Rainfall distribution, strength, and temporal variability is crucial for global food security and requires accurate prediction. By analyzing well-dated geological records, geologists and climate scientists can reconstruct past rainfall variability and causal mechanisms, providing insights into the impact of Indian Summer Monsoon.
JOURNAL OF INDIAN GEOPHYSICAL UNION
(2022)
Article
Environmental Sciences
Hai Cheng, Yao Xu, Xiyu Dong, Jingyao Zhao, Hanying Li, Jonathan Baker, Ashish Sinha, Christoph Spotl, Haiwei Zhang, Wenjing Du, Baoyun Zong, Xue Jia, Gayatri Kathayat, Dianbing Liu, Yanjun Cai, Xianfeng Wang, Nicolas M. Strikis, Francisco W. Cruz, Augusto S. Auler, Anil K. Gupta, Raj Kumar Singh, Sonu Jaglan, Som Dutt, Zhengyu Liu, R. Lawrence Edwards
Summary: The onset and termination of Heinrich Stadial 4, Chinese Stadial 4, and South American Stadial 4 were essentially synchronous, with the former leading Antarctic warming by around 300 years. The termination of Heinrich/Chinese Stadial 4 may have been triggered by a reduction in Amazon River runoff and a poleward shift of the Southern Westerly wind belt, leading to an abrupt resumption of the Atlantic Meridional Ocean Circulation.
COMMUNICATIONS EARTH & ENVIRONMENT
(2021)
Review
Multidisciplinary Sciences
Som Dutt, Anil K. Gupta, Rahul Devrani, Ram R. Yadav, Raj K. Singh
Summary: The study reveals distinct spatial variability of summer monsoon precipitation in the Indian subcontinent during the transition period, with prolonged dryness in the western parts lasting 1000 years and shorter dry spells in the northeastern parts lasting 200-300 years. Strong El Nino conditions were associated with the millennial long dryness in the western parts but had limited influence in the eastern region. More high-resolution records from different geographic regions of India are needed to confirm if regional differences occurred during the transition period.